Httpsessionbindinglistener Implementation and Application

The httpsessionbindinglistener interface has two methods to implement:
Public synchronized void valuebound (httpsessionbindingevent)
Public synchronized void valueunbound (httpsessionbindingevent)

When a session is created, the servlet container will call the valuebound method. When a session is deleted, the valueunbound method is called.

A specific application can track every logged-on user, record relevant information, and promptly Delete relevant information when it times out.

The instance code is as follows:
Import org. Apache. commons. Logging. log;
Import org. Apache. commons. Logging. logfactory;
....
....
Public synchronized void valuebound (httpsessionbindingevent ){
// Check whether it is valid
If (! Valid () return;
// Check whether the information already exists. If the information does not exist, add it.

If (info. Online. containskey (m_userid ))
{
// Record log information
Log.info ("initial user context ....");
Useronlinestruct UOS = (useronlinestruct) info. Online. Get (m_userid );
UOS. loginip = UOS. loginip;
UOS. logintime = UOS. logintime;
UOS. sessionid = UOS. sessionid;
}
Else {
Info. Online. Put (m_userid, UOS );
}
}

Public synchronized void valueunbound (httpsessionbindingevent ){
// Check whether it is valid
If (! Valid () return;
// Delete user information
// Record log information
Log.info ("destory user context ....");
Info. Online. Remove (m_userid );
}

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If you do not use log4j, you can change log.info () to system. Out. println () to get the same result.
If you want to configure log4j, click log usage

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